U.S. patent application number 09/764046 was filed with the patent office on 2002-02-21 for dielectric filter, antenna sharing device, and communication device.
This patent application is currently assigned to Murata Manufacturing Co., Ltd.. Invention is credited to Atokawa, Masayuki, Miyamoto, Hirofumi, Suemasa, Hajime, Tsunoda, Kikuo, Yamada, Yasuo.
Application Number | 20020021185 09/764046 |
Document ID | / |
Family ID | 26583719 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020021185 |
Kind Code |
A1 |
Atokawa, Masayuki ; et
al. |
February 21, 2002 |
Dielectric filter, antenna sharing device, and communication
device
Abstract
An outer conductor, an input terminal electrode, an output
terminal electrode, a voltage controllable terminal electrode, and
two separated electrodes are formed on the outer face of a
dielectric block. Furthermore, on the upper face of the dielectric
block, PIN diodes which are voltage controllable reactance
elements, and inductors for voltage-controlling the PIN diodes, and
a coupling adjustment capacitor are mounted. Frequency shifting
capacitors are formed by generation of electrostatic capacitances
between the separated electrodes and the inner conductors of the
resonance holes, respectively.
Inventors: |
Atokawa, Masayuki;
(Kanazawa-shi, JP) ; Miyamoto, Hirofumi;
(Kanazawa-shi, JP) ; Suemasa, Hajime; (Nomi-shi,
JP) ; Tsunoda, Kikuo; (Mishima-gun, JP) ;
Yamada, Yasuo; (Kanazawa-shi, JP) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
|
Assignee: |
Murata Manufacturing Co.,
Ltd.
|
Family ID: |
26583719 |
Appl. No.: |
09/764046 |
Filed: |
January 17, 2001 |
Current U.S.
Class: |
333/134 ;
333/202; 333/207 |
Current CPC
Class: |
H01P 1/2056
20130101 |
Class at
Publication: |
333/134 ;
333/202; 333/207 |
International
Class: |
H01P 001/213 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2000 |
JP |
2000-009414 |
Aug 22, 2000 |
JP |
2000-251412 |
Claims
What is claimed is:
1. A dielectric filter comprising: a dielectric block having at
least one resonance electrode, a ground electrode on the dielectric
block, input and output terminal electrodes to connect the
dielectric filter to external circuits, and a separated electrode
provided on an outer face of the dielectric block, not connected to
the input and output terminals or the ground electrode, the
separated electrode being connected to the resonance electrode via
a capacitance.
2. The dielectric filter according to claim 1, wherein either a
step or a cavity is provided on the dielectric block, and the
separated electrode is provided on the step or in the cavity.
3. The dielectric filter according to claim 1, wherein a voltage
controllable reactance element and a circuit element for
controlling the reactance element are electrically connected to the
separated electrode.
4. The dielectric filter according to claim 3, wherein either a
step or a cavity is provided on the dielectric block, and the
separated electrode is provided on the step or in the cavity.
5. The dielectric filter according to claim 3, wherein either a
step or a cavity is provided on the dielectric block, and the
separated electrode is provided on the step or in the cavity.
6. The dielectric filter according to claim 3, wherein the
dielectric block, the reactance element, and the circuit element
are mounted onto a circuit substrate, and the reactance element and
the circuit element are electrically connected to the separated
electrode via a circuit pattern provided on the circuit
substrate.
7. The dielectric filter according to claim 1, wherein the
separated electrode and the input and output terminal electrodes
are provided so as to extend on at least two outer faces of the
dielectric block.
8. The dielectric filter according to claim 1, wherein the
separated electrode and the input and output terminal electrodes
are provided at least on the under face of the dielectric
block.
9. The dielectric filter according to claim 1, wherein the number
of the separated electrodes is at least two, and the at least two
separated electrodes are electrically connected to each other by a
coupling adjustment element.
10. A dielectric filter comprising: a dielectric block having at
least one resonance hole, the dielectric block having an outer
surface including a bottom face, a conductor inserted into the
resonance hole the conductor being insulated from an inner
conductor of the resonance hole, a voltage-controllable reactance
element electrically connected to the conductor, and a circuit
substrate upon which the reactance element is mounted, disposed on
the outer surface of the dielectric block excluding the bottom face
thereof.
11. The dielectric filter according to claim 10, wherein the
voltage controllable reactance element is one of a PIN diode, a
field effect transistor, and a variable capacitance diode.
12. A dielectric filter comprising: a dielectric block having at
least one resonance hole, the dielectric block having an outer
surface including a bottom face, a conductor electrically connected
to an inner conductor of the resonance hole, a voltage-controllable
reactance element electrically connected to the conductor, and a
circuit substrate upon which the reactance element is mounted,
disposed on the outer surface of the dielectric block excluding the
bottom face thereof.
13. The dielectric filter according to claim 12, wherein the
voltage controllable reactance element is one of a PIN diode, a
field effect transistor, and a variable capacitance diode.
14. An antenna sharing device comprising a pair of filters,
respective terminals of said filters being connected together, one
of said filters being a dielectric filter according to any one of
claims 1, 3, 10 and 12.
15. A communication device comprising a high-frequency circuit
comprising one of a transmitting circuit and a receiving circuit,
said circuit including a dielectric filter according to any one of
claims 1, 3, 10 and 12.
16. A communication device comprising a high-frequency circuit
comprising one of a transmitting circuit and a receiving circuit,
said circuit being connected to a dielectric filter according to
any one of claims 1, 3, 10 and 12.
17. A communication device comprising: a transmitting circuit; a
receiving circuit; and an antenna-sharing device comprising a pair
of filters each including a first and a second terminal; the first
terminals of the filters being connected together; and the second
terminals of the filters being connected respectively to said
transmitting circuit and said receiving circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a dielectric filter for use
in a microwave band, an antenna sharing device, and a communication
device.
[0003] 2. Description of the Related Art
[0004] Conventionally, band-pass filters and band-block filters
have been known, in which a reactance element such as a PIN diode
or variable capacitance diode is connected to a coaxial dielectric
resonator, whereby the resonance frequency of each filter can be
shifted by voltage control of the reactance element.
[0005] FIG. 18 is a plan view showing the configuration of a
conventional variable frequency band-pass filter 1. FIG. 19 is an
electric circuit diagram of the band-pass filter. The filter 1
comprises resonance circuits coupled in two stages, and comprises
dielectric resonators 2 and 3, coupling capacitors C5, C6 and C7,
polarization capacitors C1 and C2 for producing an attenuation
pole, frequency shifting capacitors C3 and C4, PIN diodes D1 and D2
as reactance elements, inductors L1 and L2 to function as choke
coils, control voltage supply resistors R1 and R2, capacitors C8
and C9, and a circuit substrate 5 (FIG. 18) for mounting these
parts. Moreover, an input terminal electrode Pi, an output terminal
electrode P2, voltage control terminal electrodes CONT1 and CONT2,
and ground patterns G1 and G2 are shown.
[0006] Although the circuit of FIGS. 18-19 functions well, the
number of parts contained in the conventional variable frequency
band-pass filter 1 is large, so that miniaturization of the circuit
has been difficult. A particular problem is that the space occupied
by the circuit elements such as the PIN diodes or the like on the
circuit substrate 5 is substantially equal to the space occupied by
the dielectric resonators 2 and 3.
[0007] Moreover, conventionally, when a greater range of frequency
shift is desired, the electrostatic capacitances of the frequency
shifting capacitors C3 and C4 are increased. However, the
interaction between the frequency shifting capacitors C3 and C4 and
the PIN diodes D1 and D2 presents a problem. When the PIN diodes D1
and D2 are on, the frequency shifting capacitors C3 and C4 are
dominant, respectively, as the capacitance components of the
resonance circuits of the variable frequency band-pass filter 1
shown in FIG. 19. When the PIN diodes D1 and D2 are off, the
capacitance between the anode and cathode terminals of each of the
diodes D1 and D2 becomes dominant. For this reason, if the
capacitances of the frequency shifting capacitors C3 and C4 are
increased, there will be a large difference between the impedance
of the resonance circuit when the PIN diodes D1 and D2 are on, and
that obtained when the diodes D1 and D2 are off. Therefore, the
pass-band width obtained when the PIN diodes D1 and D2 are on (that
is, when the pass frequency of the filter 1 is low) is narrower
than that obtained when the diodes D1 and D2 are off (that is, when
the pass frequency of the filter 1 is high). Accordingly, the
available range of frequency shift has a limitation. The design
flexibility is low.
SUMMARY OF THE INVENTION
[0008] Responding to these concerns, the present invention provides
a dielectric filter which has great flexibility regarding the
available frequency shift range, has a small number of parts, and
is small in size.
[0009] The invention also provides an antenna sharing device and a
communication device using the filter.
[0010] To provide these features, according to the present
invention, there is provided a dielectric filter which comprises a
dielectric block having at least one resonance electrode, input and
output terminal electrodes to be connected to external circuits,
and a separated electrode provided on the outer face of the
dielectric block, not connected to the input and output terminals
and ground, and connected to the resonance electrode via a
capacitance. The separated electrode and the input and output
terminal electrodes are provided on the outer face of the
dielectric block or optionally on the surface of a circuit
substrate.
[0011] With the above-described configuration, the resonance
electrode provided on the dielectric block constitutes a resonator.
On the other hand, the separated electrode generates capacitance
between the separated electrode and the resonance electrode, which
functions equivalently to a frequency shifting capacitor.
Accordingly, it is unnecessary to provide a separate frequency
shifting capacitor.
[0012] Preferably, a voltage controllable reactance element and a
circuit element for controlling the reactance element are
electrically connected to the separated electrode. Thereby, the
reactance element is voltage-controlled to be switched, so that the
frequency shifting capacitor, formed by the separated electrode, is
grounded or opened to change the frequency characteristic of the
filter. Here, the dielectric block, the reactance element, and the
circuit element may be mounted onto the circuit substrate so that
the reactance element and the circuit element are electrically
connected to the separated electrode via a circuit pattern provided
on the circuit substrate. As the voltage controllable reactance
element, for example, a PIN diode, field effect transistor, or a
variable capacitance diode may be used.
[0013] Furthermore, by electrically connecting at least two
separated electrodes via the coupling adjustment element, the
filter band-widths obtained when the voltage controllable reactance
element is on and that obtained when the element is off can be
independently set. As the coupling adjustment element, for example,
a reactance element such as a capacitor, an inductor, or the like,
and a variable capacitance capacitor, and so forth may be
employed.
[0014] Moreover, according to the present invention, there is
provided a dielectric filter which comprises a dielectric block
having at least one resonance hole, a conductor inserted into the
resonance hole while the conductor is insulated from an inner
conductor of the resonance hole, a voltage-controllable reactance
element electrically connected to the conductor, and a circuit
substrate for the reactance element to be mounted onto, disposed on
an outer face of the dielectric block excluding the under face
thereof. Thereby, the inner conductor of the resonance hole and the
conductor inserted into the resonance hole form a frequency
shifting capacitor. Thus, it is unnecessary to provide a
conventional frequency shifting capacitor element.
[0015] Moreover, according to the present invention, there is
provided a dielectric filter comprising a dielectric block having
at least one resonance hole, a conductor electrically connected to
an inner conductor of the resonance hole, a voltage-controllable
reactance element electrically connected to the conductor, and a
circuit substrate for the reactance element to be mounted onto,
disposed on an outer face of the dielectric block excluding the
under face thereof. Onto the circuit substrate, a circuit element
for controlling the frequency shifting capacitor element and the
reactance element, and so froth may be mounted in addition to the
reactance elements.
[0016] Preferably, either a step or a concavity is provided on the
dielectric block, and the separated electrode is provided on the
step or in the concavity. Thus, since the reactance element and the
circuit element are mounted on the step or in the concavity, the
dielectric filter is reduced in size.
[0017] The antenna sharing device and the communication device of
the present invention each include at least one of the dielectric
filters having the above-described characteristics. Therefore, the
design flexibility can be enhanced, and the size can be
reduced.
[0018] Other features and advantages of the present invention will
become apparent from the following description of the invention
which refers to the accompanying drawings, in which like references
denote like elements and parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is an exploded perspective view of a dielectric
filter according to a first embodiment of the present
invention;
[0020] FIG. 2 is an electrically equivalent circuit diagram of the
dielectric filter of FIG. 1;
[0021] FIG. 3 is an electric circuit diagram illustrating the
operation of the dielectric filter, when a PIN diode is on.
[0022] FIG. 4 is an electric circuit diagram illustrating the
operation of the filter when the PIN diode is off.
[0023] FIG. 5 is an exploded perspective view of a dielectric
filter according to a second embodiment of the present
invention;
[0024] FIG. 6 is an exploded perspective view of a dielectric
filter according to a third embodiment of the present
invention;
[0025] FIG. 7 is an exploded perspective view of a dielectric
filter according to a fourth embodiment of the present
invention;
[0026] FIG. 8 is an exploded perspective view of a dielectric
filter according to a fifth embodiment of the present
invention;
[0027] FIG. 9 is an exploded perspective view of a dielectric
filter according to a sixth embodiment of the present
invention;
[0028] FIG. 10 is an exploded perspective view of a dielectric
filter according to a seventh embodiment of the present
invention;
[0029] FIG. 11 is an exploded perspective view of a dielectric
filter according to a eighth embodiment of the present
invention;
[0030] FIG. 12 is an exploded perspective view of a dielectric
filter according to a ninth embodiment of the present
invention;
[0031] FIG. 13 is a cross sectional view taken along line XIII-XIII
before the PIN diodes a re mounted as shown in FIG. 12;
[0032] FIG. 14 is a cross sectional view taken along line XIV-XIV
before the PIN diodes are mounted as shown in FIG. 12;
[0033] FIG. 15 is an exploded perspective view of a dielectric
filter according to a tenth embodiment;
[0034] FIG. 16 is an electric circuit block diagram of an antenna
sharing device according to an embodiment of the present
invention;
[0035] FIG. 17 is an electric circuit block diagram of a
communication device according to an embodiment of the present
invention;
[0036] FIG. 18 is a plan view of a conventional dielectric filter;
and
[0037] FIG. 19 is an electric circuit diagram of the dielectric
filter of FIG. 18.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0038] Hereinafter, embodiments of the dielectric filter, the
antenna sharing device, and the communication device of the present
invention will be described with reference to the accompanying
drawings. In the respective embodiments, similar components and
similar parts are designated by the same reference numerals, and
the repeated description is omitted.
[0039] (First Embodiment, FIGS. 1 to 4)
[0040] A variable frequency band-pass dielectric filter 11 contains
a single dielectric block 12 having a substantially rectangular
parallelepiped shape, as shown in FIG. 1. In the dielectric block
12, two resonance holes 13 and 14 are formed so as to pass through
the opposing end faces 12a and 12b of the block 12. The resonance
holes 13 and 14 are arranged so that the axes thereof are in
parallel to each other in the dielectric block 12. The resonance
holes 13 and 14 each have a circular cross section. Inner
conductors 16 are formed on the inner walls of the resonance holes
13 and 14. The resonance holes 13 and 14 and the inner conductors
16 form resonance electrodes, respectively. The resonance holes 13
and 14 are coupled by electromagnetic fields to each other.
[0041] A step 18 is formed on the upper face 12c of the dielectric
block 12 so as to form a lower portion 19. Separated electrodes 24
and 25 are formed on the lower portion 19. Chip parts (described
later) such as the PIN diodes D11 and D12, and so forth are also
mounted on the lower portion 19. Accordingly, because the chip
parts are mounted onto the lower portion 19 of the upper face 12c
of the dielectric block 12, the overall height of the filter 11 can
be reduced and made small. Needless to say, it is not necessary to
form the step 18 on the upper face 12c of the dielectric block
12.
[0042] On the outer face of the dielectric block 12, an outer
conductor 17, an input terminal electrode 21, an output terminal
electrode 22, a voltage control terminal electrode 23, and the two
separated electrodes 24 and 25 are formed. The outer conductor 17
is formed on the outer face of the dielectric block 12 excluding
the area where the electrodes 21 to 25 are formed and also
excluding one opening end face 12a (hereinafter, referred to as an
opening end face 12a) of the dielectric block 12 at which the
resonance holes 13 and 14 are opened.
[0043] The input and output terminal electrodes 21 and 22 are
formed so as to extend from the right and left side-faces 12d and
12e of the dielectric block 12, respectively, and then to bend and
extend onto the under face 12f. The voltage control terminal
electrode 23 extends from the upper face 12c of the dielectric
block 12 onto the under face 12f via the side face 12e. The under
face 12f is used as a mounting face of the dielectric filter 11.
The dielectric filter 11 is mounted onto a printed board or the
like with the under face 12f being positioned downward. The
separated electrodes 24 and 25 are formed on the upper face 12c of
the dielectric block 12 so as not to be connected to the outer
conductor 17 and the other electrodes 21 to 23.
[0044] The inner conductors 16 of the resonance holes 13 and 14 are
electrically opened (separated) from the outer conductor 17 at the
opening side end face 12a, and are electrically short-circuited to
the outer conductor 17 at the other opening end face 12b
(hereinafter, referred to as a short-circuited end face 12b).
Accordingly, in the dielectric block 12, the resonance holes 13 and
14 and the inner conductors 16 form 1/4 wavelength dielectric
resonators R1 and R2, respectively.
[0045] Moreover, PIN diodes D11 and D12 as the voltage controllable
reactance elements, and inductors L11 and L12 for
voltage-controlling the PIN diodes D11 and D12, and a coupling
adjustment capacitor C1, are mounted onto the upper face 12c of the
dielectric block 12. The PIN diode D11 is electrically connected
between the outer conductor 17 and the separated electrode 24 by
means of solder or a conductive adhesive. The PIN diode D12 is
electrically connected between the outer conductor 17 and the
separated electrode 25. The inductor L11 and the coupling
adjustment capacitor C11 are connected in parallel to each other
between the separated electrodes 24 and 25. The inductor L12 is
electrically connected between the separated electrode 25 and the
voltage control terminal electrode 23.
[0046] For the purpose of facilitating soldering work for the
respective components, a solder resist film may be printed on the
lower portion 19 of the upper face 12c. Moreover, the opening end
face 12a of the dielectric block 12 may be covered with a metallic
sheet or the like for enhancement of the electromagnetic shielding
of the dielectric filter 11.
[0047] FIG. 2 shows an electrically equivalent circuit diagram of
the dielectric filter 11 constituted as described above. The
dielectric filter 11 includes resonance circuits coupled in two
stages. The dielectric resonator R1 is electrically connected to
the input terminal electrode 21 via a coupling capacitor C13. The
dielectric resonator R2 is electrically connected to the output
terminal electrode 22 via a coupling capacitor C14.
[0048] The coupling capacitor C13 is formed, due to the generation
of electrostatic capacitance between the input terminal electrode
21 and the inner conductor 16 of the resonance hole 13. The
coupling capacitor C14 is formed, due to the generation of
electrostatic capacitance between the output terminal electrode 22
and the inner conductors 16 of the resonance hole 14. The
dielectric resonators R1 and R2 are electromagnetic field coupled
(indicated by reference character K in FIG. 2), caused by the inner
conductors 16 of the resonance holes 13 and 14 opposed to each
other at an predetermined interval. Furthermore, electrostatic
capacitances are generated between the input and output terminal
electrodes 21 and 22 and the outer conductor 17, and thereby,
capacitors C12 and C15 are formed with one end of each being
grounded, respectively.
[0049] A frequency shifting capacitor Cs1 is formed, due to
generation of an electrostatic capacitance between the separated
electrode 24 and the inner conductor 16 of the resonance hole 13.
Similarly, a frequency shifting capacitor Cs2 is formed, due to
generation of an electrostatic capacitance between the separated
electrode 25 and the inner conductor 16 of the resonance hole 14.
That is, one end of the frequency shifting capacitor Cs1 is
electrically connected to the open end of the dielectric resonator
R1 via the capacitance, and the other end is electrically connected
to the anode of the PIN diode D11. Similarly, one end of the
frequency shifting capacitor Cs2 is electrically connected to the
open end of the dielectric resonator R2 via the capacitance, and
the other end is electrically connected to the anode of the PIN
diode D12. The cathodes of the PIN diodes D11 and D12 are grounded,
respectively.
[0050] The parallel circuit of the inductor (choke coil) L11 and
the coupling adjustment capacitor C11 is connected between an
intermediate connection point of the anode of the PIN diode D11 and
the frequency shifting capacitor Cs1, and that of the anode of the
PIN diode D12 and the frequency shifting capacitor Cs2.
[0051] The voltage control terminal electrode 23 is electrically
connected to the anode of the PIN diode D12 via the choke coil
inductor L12, and moreover, is electrically connected to the anode
of the PIN diode D11 via the inductors L11 and L12.
[0052] As described above, in the dielectric filter 11, the
frequency shifting capacitors Cs1 and Cs2 are formed by the
separated electrodes 24 and 25 provided on the upper face of the
dielectric block 12, and the inner conductors 16 of the resonance
holes 13 and 14, respectively. Moreover, coupling between the
dielectric resonators R1 and R2 is performed by utilizing the
electromagnetic coupling K between the inner conductors 16 of the
resonance holes 13 and 14. That is, the conventional frequency
shifting capacitors and the conventional coupling capacitor between
the resonators (equivalent to the coupling capacitor C6 in FIG.
18), which are separate parts from the dielectric resonators, can
be omitted.
[0053] Moreover, the chip parts such as the PIN diodes D11 and D12
or the like are mounted directly onto the dielectric block 12.
Accordingly, the area occupied by the printed circuit substrate or
the like of a communication device can be reduced by an amount
corresponding to the direct coupling of the chip parts.
Furthermore, the filter 11 having a desired attenuation pole can be
obtained by appropriately designing the shapes of the resonance
electrodes or those of the dielectric block, e.g., by forming large
and small size portions in the resonance holes to produce a step
structure. Accordingly, it is also unnecessary to provide a
conventional polarization capacitor. Thus, the filter can be even
more reduced in size.
[0054] Next, the working effects of the dielectric filter 11 will
be described.
[0055] The pass frequency of the dielectric filter 11 is determined
by the resonance frequency of a resonance system comprising the
frequency shifting capacitor Cs1 and the dielectric resonator R1
and that of a resonance system comprising the frequency shifting
capacitor Cs2 and the dielectric resonator R2. That is, when a
positive control voltage is applied to the voltage control terminal
electrode 23, the PIN diodes D11 and D12 are turned on.
Accordingly, as shown in FIG. 3, the frequency shifting capacitors
Cs1 and Cs2 are grounded via the PIN diodes D11 and D12,
respectively, so that the pass frequency is decreased. At this
time, the coupling adjustment capacitor C11 exerts no influence,
since it is grounded. The dielectric resonators R1 and R2 are
coupled to each other via electromagnetic coupling K. Thus, the
pass bandwidth of the dielectric filter 11 is set.
[0056] To the contrary, when a negative voltage is applied as a
control voltage to the voltage control terminal electrode 23, the
PIN diodes D11 and D12 are turned off. Thereby, as shown in FIG. 4,
the frequency shifting capacitors Cs1 and Cs2 become open, and the
pass frequency is increased. Then, the dielectric resonators R1 and
R2 are coupled to each other via the electromagnetic field coupling
K and the capacitive coupling caused by the frequency shifting
capacitors Cs1 and Cs2, and the coupling adjustment capacitor C11.
Accordingly, the pass bandwidth obtained when the PIN diodes D11
and D12 are off and that obtained when the PIN diodes D11 and D12
are on can be set independently with a reduced number of parts and
a small current consumption.
[0057] As described above, the dielectric filter 11 has two
different pass frequency characteristics, and moreover, the
respective pass bandwidths can be independently set. In the first
embodiment, the capacitor C11 is used for adjustment of coupling
between the dielectric resonators R1 and R2. However, an inductor
or a voltage controllable reactance element such as a variable
capacitance capacitor or the like may be used, if necessary.
[0058] (Second Embodiment, FIG. 5)
[0059] In a variable frequency dielectric filter 31, the outer
conductor 17, the input terminal electrode 21, the output terminal
electrode 22, and the two separated electrodes 34 and 35 are formed
as shown in FIG. 5. The voltage-control terminal is not shown in
FIG. 5 but can be provided as taught according to the other
embodiments.
[0060] The separated electrodes 34 and 35 are formed on the opening
end-face 12a of the dielectric block 12 so as not to be
electrically connected to the outer conductor 17 and the input and
output terminal electrodes 21 and 22. The separated electrode 35 is
extended from the opening end-face 12a onto the under face 12f. A
part of each of the respective separated electrodes 34 and 35 is
extended into the corresponding one of the resonance holes 13 and
14. The inner conductors 16 of the resonance holes 13 and 14 serve
as the resonance electrodes are opposed to the separated electrodes
34 and 35 which extend into the resonance holes 13 and 14 so as to
define conductor-free gaps 32, in the vicinity of the opening
end-face 12a, respectively.
[0061] Moreover, the PIN diodes D11 and D12 and the coupling
adjustment capacitor C11 are mounted on the opening end-face 12a of
the dielectric block 12. The PIN diode D11 is electrically
connected between the outer conductor 17 and the separated
electrode 34. The PIN diode D12 is electrically connected between
the outer conductor 17 and the separated electrode 35. The coupling
adjustment capacitor C11 is electrically connected between the
separated electrodes 34 and 35.
[0062] In the dielectric filter 31 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
the separated electrode 34 and the inner conductor 16 of the
resonance hole 13 which opposes each other so as to sandwich the
gap 32 and generate capacitive coupling between the separated
electrode 34 and the inner conductor 16. Similarly, the frequency
shifting capacitor Cs2 is formed by the separated electrode 35 and
the inner conductor 16 of the resonance hole 14 which oppose each
other so as to sandwich the conductor gap 32 and generate
electrostatic capacitive coupling between the separated electrode
35 and the inner conductor 16. As a result, the dielectric filter
31 can be reduced in size. As compared with the filter 11 of the
above-described described first embodiment, the height of the
dielectric filter 31 can even be more reduced.
[0063] (Third Embodiment, FIG. 6)
[0064] As shown in FIG. 6, in a variable frequency dielectric
filter 41, the outer electrode 17, the input terminal electrode 21,
the output terminal electrode 22, the voltage control terminal
electrode 23, and two separated electrodes 44 and 45 are formed on
the outer face of the dielectric block 12.
[0065] The separated electrodes 44 and 45 are formed on the opening
end face 12a of the dielectric block 12 so as not to be
electrically connected to the outer conductor 17 and the other
electrodes 21 to 23. The separated electrode 44 extends from the
opening end-face 12a onto the side face 12e. The separated
electrode 45 extends from the opening end-face 12a onto the side
face 12d. A part of the respective separated electrodes 44 and 45
extend into the resonance holes 13 and 14. The inner conductors 16
of the resonance holes 13 and 14, which function as resonance
electrodes, are opposed, via the conductor gaps 32, to the
separated electrodes 44 and 45 in the resonance holes 13 and 14, in
the vicinity of the opening end-face 12a, respectively.
[0066] Moreover, the PIN diodes D11 and D12 are mounted to both of
the side faces 12e and 12d of the dielectric block 12,
respectively. The inductors L11 and L12 are mounted onto the
opening end-face 12a. The PIN diode D11 is electrically connected
between the outer conductor and the separated electrode 44. The PIN
diode D12 is electrically connected between the outer conductor 17
and the separated electrode 45. The inductor L11 is electrically
connected between the separated electrodes 44 and 45. The inductor
L12 is electrically connected between the separated electrode 45
and the voltage control terminal electrode 23.
[0067] In the dielectric filter 41 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
the separated electrode 44 and the inner conductor 16 of the
resonance hole 13 which oppose each other via the conductor gap 32
and generate electrostatic capacitive coupling between the
separated electrode 44 and the inner conductor 16 of the resonance
hole 13. Similarly, the frequency shifting capacitor Cs2 is formed
by the separated electrode 45 and the inner conductor 16 of the
resonance hole 14 which oppose each other via the conductor gap 32
to generate electrostatic capacitive coupling between the separated
electrode 45 and the inner conductor 16. As a result, the
dielectric filter 41 can be reduced in size.
[0068] (Fourth Embodiment, FIG. 7)
[0069] As shown in FIG. 7, in a variable frequency dielectric
filter 51, the dielectric block 12 is mounted onto a circuit
substrate 60 having the PIN diodes D11 and D12 and the inductors
L11 and L12 mounted thereto.
[0070] On the upper face of the circuit substrate 60, an input
electrode pattern 61, an output electrode pattern 62, and a voltage
control electrode pattern 63, relay electrode patterns 65 and 66,
and a wide area ground pattern 64 are formed. The PIN diode D11 is
electrically connected between the ground pattern 64 and the relay
electrode pattern 65. The PIN diode D12 is electrically connected
between the ground pattern 64 and the relay electrode pattern 66.
The inductor L11 is electrically connected between the relay
electrode patterns 65 and 66. The inductor L12 is electrically
connected between the relay electrode pattern 66 and the voltage
control electrode pattern 63.
[0071] Meanwhile, on the outer face of the dielectric block 12, the
outer conductor 17, the input terminal electrode 21, the output
terminal electrode 22, and two separated electrodes 54 and 55 are
formed. The separated electrodes 54 and 55 are formed on the under
face 12f of the dielectric block 12, respectively, so as not to be
electrically connected to the outer conductor 17 and the input and
output terminal electrodes 21 and 22.
[0072] The dielectric block 12 is mounted onto the circuit
substrate 60 by use of solder, an electrically conductive adhesive,
or the like. Thereby, the input terminal electrode 21 of the
dielectric block 12 is electrically connected to the input
electrode pattern 61 of the circuit substrate 60. Similarly, the
output terminal electrode 22 is electrically connected to the
output electrode pattern 62. The separated electrodes 54 and 55 are
electrically connected to the relay electrode patterns 65 and 66,
respectively. The outer conductor 17 is electrically connected to
the ground pattern 64.
[0073] In the dielectric filter 51 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed, due
to generation of an electrostatic capacitance between the separated
electrode 54 and the inner conductors 16 of the resonance holes 13.
Similarly, the frequency shifting capacitor Cs2 is formed, due to
generation of an electrostatic capacitance between the separated
electrode 55 and the inner conductors 16 of the resonance holes 14.
Accordingly, the dielectric filter 51 has the same equivalent
electric circuit as that of the electric circuit of FIG. 2
excepting that the coupling adjustment capacitor C11 is excluded.
As a result, the small-sized dielectric filter 51 can be
obtained.
[0074] (Fifth Embodiment, FIG. 8)
[0075] As shown in FIG. 8, a variable frequency dielectric filter
71 comprises a circuit substrate 80 having the PIN diodes D11 and
D12 and the inductors L11 and L12 mounted thereto, bonded to the
opening end-face 12a of the dielectric block 12.
[0076] On the front side of the circuit substrate 80, relay
electrode patterns 81 and 82, a ground pattern 85, and a voltage
control electrode pattern 86 are formed. The relay electrode
patterns 81 and 82 are connected to relay electrode patterns 81a
and 82a formed on the back side of the circuit substrate 80, via
through-holes 83 provided in the circuit substrate 80. The PIN
diode D11 is electrically connected between the ground pattern 85
and the relay electrode pattern 82. The PIN diode D12 is
electrically connected between the ground pattern 85 and the relay
electrode pattern 81. The inductor L11 is electrically connected
between the relay electrode patterns 81 and 82. The inductor L12 is
electrically connected between the relay electrode pattern 81 and
the voltage control electrode pattern 86.
[0077] Meanwhile, the outer conductor 17, the input terminal
electrode 21, the output terminal electrode 22, two separated
electrodes 74 and 75 are formed on the outer surface of the
dielectric block 12. The separated electrodes 74 and 75 are formed
on the opening end-face 12a of the dielectric block 12 so as not to
be electrically connected to the outer conductor 17, and the input
and output terminal electrodes 21 and 22. The inner conductors of
the resonance holes 13 and 14 are opposed, via the conductor gaps
32, to the separated electrodes 74 and 75 elongating in the
resonance hole 13 and 14, so as to sandwich the gap 32, in the
vicinity of the opening end face 12a.
[0078] When the circuit substrate 80 is bonded to the opening end
face 12a of the dielectric block 12, the relay electrode patterns
81a and 82a of the circuit substrate 80 are electrically connected
to the separated electrodes 74 and 75 of the dielectric block 12,
respectively.
[0079] In the dielectric filter 71 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
the separated electrode 75 and the inner conductor 16 of the
resonance hole 13 opposed to each other so as to sandwich the
conductor gaps 32 and generate electrostatic capacitive coupling,
respectively. Similarly, the frequency shifting capacitor Cs2 is
formed by the separated electrode 74 opposed to the inner conductor
16 of the resonance hole 14 so as to sandwich the conductor gap 32
and generate electrostatic capacitive coupling.
[0080] Accordingly, the dielectric filter 71 has substantially the
same equivalent circuit as that of the electric circuit shown in
FIG. 2 excepting that the coupling adjustment capacitor C11 is
excluded. As a result, the dielectric filter 71 can be reduced in
size. The height of the filter 71 can be even more reduced as
compared with the filter 51 of the fourth embodiment.
[0081] (Sixth Embodiment, FIG. 9)
[0082] In the dielectric filters described in the first to fifth
embodiments, the frequency shifting capacitors are formed by means
of the separated electrodes formed on the surfaces of the
dielectric blocks, respectively. However, in some cases, with such
separated electrodes, electrostatic capacitances can not be
satisfactorily produced. Accordingly, in the sixth embodiment, a
dielectric filter containing a frequency shifting coupling
capacitor having a large electrostatic capacitance is
described.
[0083] As shown in FIG. 9, a variable frequency dielectric filter
91 comprises the dielectric block 12, the circuit substrate 80
having the PIN diodes D11 and D12 or the like mounted thereon,
insulation members 92 and 93 having a desired dielectric constant,
and metallic pins 94 and 95 having the same function as the
separated electrodes. The columnar insulation members 92 and 93,
while they have the metallic pins 94 and 95 inserted under pressure
into the central axial portions thereof, are inserted into the
resonance holes 14 and 13, respectively. The circuit substrate 80
is arranged so as to be opposed to the opening end-face 12a of the
dielectric block 12, and the heads of the metallic pins 94 and 95
are inserted through the through-holes 83 of the circuit-substrate
80 and soldered.
[0084] In the dielectric filter 91 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
generation of an electrostatic capacitance between the metallic pin
95 and the inner conductor 16 of the resonance hole 13. The
frequency shifting capacitor Cs2 is formed by generation of an
electrostatic capacitance between the metallic pin 94 and the inner
conductor 16 of the resonance hole 14. Thus, the frequency shifting
capacitors Cs1 and Cs2 have the structure of a so-called coaxial
capacitor, and therefore, have a large electrostatic capacitance,
respectively. The dielectric capacitor 91 has substantially the
same equivalent circuit as that of the electric circuit of FIG. 2
excepting that the coupling adjustment capacitor C11 is
excluded.
[0085] In the dielectric capacitor 91, the input and output
terminal electrodes 21 and 22 may be provided on the circuit
substrate 80, not on the front surface of the dielectric block 12.
Moreover, the electromagnetic shielding may be enhanced by
providing the conductor gaps 32 in the inner conductors 16 of the
resonance holes 13 and 14 as shown in FIG. 5, and by covering the
opening end face 12a of the dielectric block 12 with the outer
conductor 17.
[0086] (Seventh Embodiment, FIG. 10)
[0087] In the seventh embodiment, the frequency shifting capacitors
Cs1 and Cs2 are formed of the chip capacitors, if a sufficient
electrostatic capacitance can not be obtained by means of the
separated electrodes formed on the surface of the dielectric block.
As shown in FIG. 10, a variable frequency dielectric filter 101
comprises the dielectric block 12, the circuit substrate 80 having
the PIN diodes D11 and D12 and so forth mounted thereto, and
connecting members 102 and 103. The connecting members 102 and 103
are formed by punching a metallic sheet having a spring-like
property, and working the metallic sheet by bending it. The
connecting members 102 and 103 are electrically connected to the
inner conductors 16 by inserting the feet 104 thereof having a
spring-like property into the resonance holes 14 and 13,
respectively. Thus, the members 102 and 103 are secured to the
dielectric block 12.
[0088] The circuit substrate 80 is arranged so as to be opposed to
the opening end-face 12a of the dielectric block 12. The heads of
the connecting members 102 and 103 are soldered to the relay
electrode patterns 81a and 82a formed on the back side of the
circuit substrate 80. On the front side of the circuit substrate
80, the relay electrode patterns 81, 82, 88a, and 88b, the voltage
control electrode pattern 86, and the voltage control electrode
pattern 86, and the ground patterns 89a and 89b are provided. To
the circuit substrate 80, the chip capacitors Cs1 and Cs2 as the
frequency shifting capacitors are mounted, in addition to the PIN
diodes D11 and D12 and the inductors L11 and L12.
[0089] (Eighth Embodiment, FIG. 11)
[0090] The eighth embodiment is substantially the same as the first
embodiment excepting that a concavity 112 is provided, instead of
the step 18 of the dielectric filter 11 of the first embodiment. As
shown in FIG. 11, in the variable frequency dielectric filter 111,
the concavity 112 is formed on the upper face 12c of the dielectric
block 12.
[0091] The two separated electrodes 24 and 25, together with a part
of the outer conductor 17 and the voltage control terminal
electrode 23, are formed in the concavity 112 on the upper face 12c
of the dielectric block 12 so as not to be electrically connected
to the outer conductor 17 and the other electrodes 21 to 23. In the
concavity 112, the PIN diodes D11 and D12, and the inductors L11
and L12 are mounted. The PIN diode D11 is electrically connected
between the outer conductor 17 and the separated electrode 24. The
PIN diode D12 is electrically connected between the outer conductor
17 and the separated electrode 25. The inductor L11 is electrically
connected between the separated electrodes 24 and 25 in parallel to
them. The inductor L12 is electrically connected between the
separated electrode 25 and the voltage control terminal electrode
23.
[0092] In the dielectric filter 111 having the above-described
configuration, the frequency shifting capacitors Cs1 and Cs2 are
formed by the separated electrodes 24 and 25 formed on the upper
face 12c of the dielectric block 12 and the inner conductors 16 of
the resonance holes 13 and 14. Furthermore, the PIN diodes D11 and
D12 and the inductors L11 and L12 are mounted in the concavity 112
on the upper face 12c of the dielectric block 12. Accordingly, the
dielectric filter 111 can be reduced in size.
[0093] (Ninth Embodiment, FIGS. 12 to 14)
[0094] FIG. 12 is an exploded perspective view showing the ninth
embodiment of the dielectric filter of the present invention. FIG.
13 is a cross section taken along line XIII-XIII before the PIN
diodes are mounted as shown in FIG. 12. FIG. 14 is a cross section
taken along line XIV-XIV before the PIN diodes are mounted as shown
in FIG. 12.
[0095] As shown in FIG. 12, the variable frequency band-pass
dielectric filter 121 is substantially the same as the dielectric
filter 11 of the first embodiment, excepting that the PIN diodes
D11 and D12 are mounted in the resonance holes 13 and 14,
respectively. Concretely, the outer conductor 17, the input
terminal electrode 21, the output terminal electrode 22, and the
separated electrodes 24 and 25 are formed on the outer face of the
single dielectric block 12 having a substantially rectangular
parallelepiped shape. A step 18 is formed on the upper face 12c of
the dielectric block 12. The inductors L11 and L12 are mounted on
the lower portion 19 of the upper face 12c. Furthermore, the PIN
diodes D11 and D12 are formed in the resonance holes 13 and 14. For
the purpose of mounting the PIN diodes D11 and D12, the hole
diameters at the opening end-face 12a of the resonance holes 13 and
14 are set to be larger than those at the short-circuited end-face
12b thereof.
[0096] The separated electrodes 24 and 25 are formed on the lower
portion 19 on the upper face 12c of the dielectric block 12 so as
not to be electrically connected to the outer conductor 17 and the
voltage control terminal electrode 23. As shown in FIG. 13, the
separated electrodes 24 and 25 extend from the upper face 12c to
substantially central positions within the resonance holes 13 and
14 via the opening end-face 12a and the inner wall upper-surfaces
of the resonance holes 13 and 14, respectively. The separated
electrodes 24 and 25 are extended around the whole of the
circumferences of the inner wall surfaces of the resonance holes 13
and 14 substantially in the centers of the resonance holes 13 and
14, respectively (FIG. 13). The inner conductors 16 of the
resonance holes 13 and 14 are opposed at respective gaps 32 to the
separated electrodes 24 and 25 in the resonance holes 13 and 14.
Furthermore, as shown in FIG. 14, the outer conductor 17 is
elongated onto the inner wall lower-surfaces of the resonance holes
13 and 14, in the vicinity of the opening end-face 12a.
[0097] The PIN diode D11 is electrically connected between the
outer conductor 17 and the separated electrode 24 in the resonance
hole 13. The PIN diode D12 is electrically connected between the
outer conductor 17 in the resonance hole 14 and the separated
electrode 25 in the resonance hole 14. The inductor L11 is
electrically connected between the separated electrodes 24 and 25.
The inductor L12 is electrically connected between the separated
electrode 25 and the voltage control terminal electrode 23.
[0098] In the dielectric filter 121 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
the separated electrode 24 and the inner conductor 16 of the
resonance hole 13 opposed to each other so as to sandwich the
conductor gap 32. Similarly, the frequency shifting capacitor Cs2
is formed by the separated electrode 25 and the inner conductor 16
of the resonance hole 13 opposed to each other so as to sandwich
the conductor gap 32. Moreover, the inductors L11 and L12 are
mounted onto the lower portion 19 of the step 18, and moreover, the
PIN diodes D11 and D12 are mounted in the resonance holes 13 and
14, respectively. Therefore, the dielectric filter 121 can be
reduced in size.
[0099] (Tenth Embodiment, FIG. 15)
[0100] As shown in FIG. 15, the tenth embodiment is the same as the
second embodiment, excepting that a concavity 132 is formed on the
opening end-face 12a of the dielectric block 12 of the dielectric
filter 31.
[0101] The separated electrodes 34 and 35, together with a part of
the outer conductor 17, are formed in the concavity 132 on the
opening end-face 12a of the dielectric block 12 so as not to be
electrically connected to the outer conductor 17 and the input and
output terminal electrodes 21 and 22. The separated electrode 35 is
elongated from the opening end-face 12a onto the under face 12f.
Respective parts of the separated electrodes 34 and 35 are
elongated in the resonance holes 13 and 14. The inner conductors 16
of the resonance holes 13 and 14 are opposed to the separated
electrodes 34 and 35 elongating in the resonance holes 13 and 14 so
as to sandwich the conductor gaps 32, in the vicinity of the
opening end face 12a, respectively.
[0102] Moreover, the PIN diodes D11 and D12, and the coupling
adjustment capacitor C11 are mounted in the concavity 132 on the
opening end face 12a of the dielectric block 12. The PIN diode D11
is electrically connected between the outer conductor 17 and the
separated electrode 34. The PIN diode D12 is electrically connected
between the outer conductor 17 and the separated electrode 35. The
coupling adjustment capacitor C11 is electrically connected between
the separated electrodes 34 and 35.
[0103] In the dielectric filter 131 having the above-described
configuration, the frequency shifting capacitor Cs1 is formed by
the separated electrode 34 and the inner conductor 16 of the
resonance hole 13 opposed to each other so as to sandwich the
conductor gap 32. Moreover, the PIN diodes D11 and D12 and the
coupling adjustment capacitor C11 are mounted in the concavity 132
on the opening side end face 12a of the dielectric block 12.
Therefore, the dielectric filter 131 can be reduced in size.
[0104] (Eleventh Embodiment, FIG. 16)
[0105] The eleventh embodiment describes an embodiment of the
antenna sharing device of the present invention. As shown in FIG.
16, in an antenna sharing device 141, a transmission filter 142 is
electrically connected between a transmission terminal Tx and an
antenna terminal ANT. A reception filter 143 is electrically
connected between a reception terminal Rx and the antenna terminal
ANT. Here, as the transmission filter 142 or the reception filter
143, or both, the filters 11, 31, 41, 51, 71, 91, 101, 111, 121,
and 131 of the first to tenth embodiments may be employed. By
mounting the filter 11 or the like, the antenna sharing device 141
of which the design flexibility is large, and the size is reduced
can be realized.
[0106] (Twelfth Embodiment, FIG. 17)
[0107] The twelfth embodiment describes an embodiment of the
communication device of the present invention by way of a portable
telephone.
[0108] FIG. 17 is an electric circuit block diagram of the RF part
of a portable telephone 150. In FIG. 17, an antenna element 152, a
duplexer 153, a transmission side isolator 161, a transmission side
amplifier 162, a transmission side interstage band-pass filter 163,
a reception side amplifier 165, a reception side interstage band
pass filter 166, a reception side mixer 167, a voltage control
oscillation device (VCO) 168, and a local band-pass filter 169 are
shown.
[0109] Here, as the duplexer 153, for example, the antenna sharing
device 141 of the above-described eleventh embodiment can be
employed. Furthermore, as the transmission-side and/or
reception-side interstage band-pass filters 163 and 166, and/or the
local band-pass filter 169, for example, the dielectric filters 11,
31, 41, 51, 71, 91, 101, 111, 121, and 131 of the first to tenth
embodiments, or the like can be employed. By mounting the antenna
sharing device 141, the dielectric filter 11, or the like, the
design flexibility of the RF part can be enhanced, and a small
sized portable telephone can be realized.
[0110] (Other Embodiments)
[0111] The dielectric filter, the antenna sharing device, and the
communication device of the present invention are not limited to
the above-described embodiments, and can be variously modified
without departing from the spirit and scope of the invention. As
the voltage controllable reactance element, a field effect
transistor, a variable capacitance diode, or the like may be
employed. Furthermore, the dielectric block may have at least one
resonance hole.
[0112] As described above, according to the present invention,
predetermined capacitances are generated between the separated
electrodes and the resonance electrodes, and are used as
capacitance components equivalent to the frequency shifting
capacitors. Accordingly, conventional frequency shifting capacitor
elements can be omitted. By electrically connecting the voltage
controllable reactance element and the circuit element for
controlling the reactance element to the separated electrodes, the
reactance element can be voltage controlled to be switched whereby
the frequency shifting coupling capacitors formed by the separated
electrodes are grounded or opened to shift the frequency
characteristic of the filter.
[0113] Moreover, by electrically connecting at least two separated
electrodes via the coupling adjustment element, the coupling degree
between the resonators obtained when the voltage controllable
reactance element is on, and that obtained when the voltage
controllable reactance element is off can be independently set by
use of a smaller number of parts and less current consumption. As a
result, an antenna device and a communication device of which the
design flexibilities are large, and the sizes are reduced can be
obtained.
[0114] The dielectric filter in accordance with the present
invention may comprise a dielectric block having at least one
resonance hole, a conductor inserted into the resonance hole while
the conductor is insulated from an inner conductor of the resonance
hole, a voltage-controllable reactance element electrically
connected to the conductor, and a circuit substrate for the
reactance element to be mounted onto, disposed on an outer face of
the dielectric block excluding the under face thereof. Accordingly,
a conventional frequency shifting capacitor doesn't need to be
provided, since the inner conductor in the resonance hole and the
conductor inserted into the resonance hole form a frequency
shifting capacitor.
[0115] The dielectric filter in accordance with the present
invention may comprise a dielectric block having at least one
resonance hole, a conductor electrically connected to an inner
conductor of the resonance hole, a voltage-controllable reactance
element electrically connected to the conductor, and a circuit
substrate for the reactance element to be mounted onto, disposed on
an outer face of the dielectric block excluding the under face
thereof. Therefore, on the circuit substrate, a circuit element for
controlling the frequency shifting capacitor element and the
reactance element, and so forth can be mounted. Thus, the filter
can be reduced in size.
[0116] Preferably, either a step or a concavity may be provided on
the dielectric block, and the separated electrode is provided on
the step or in the concavity. Since the reactance element and the
circuit element can be mounted on the step or in the concavity. the
size of the dielectric filter can be reduced.
[0117] Although the present invention has been described in
relation to particular embodiments thereof, many other variations
and modifications and other uses will become apparent to those
skilled in the art. Therefore, the present invention is not limited
by the specific disclosure herein.
* * * * *